A presentation system is known (refer to Patent Document #1) in which a user issues commands to a projector device which projects a picture or the like upon a screen or the like for proceeding from the current projection contents to the next picture, drawing underlining under projection contents, zooming projection contents and the like, from a position which is away from the projector device. In the Patent Document #1, there is disclosed a technique in which a laser beam is projected by a laser pointer upon a presentation picture, the presentation picture which is being projected and the laser spot are photographed at a frame rate of 10 frames per second using an electronic camera, and the commands are specified based upon the movement and the position of the laser spot which are obtained based upon the pictures which have been photographed.    Patent Document #1: Japanese Laid-Open Patent Publication 2001-125738